1. Field of the Invention
The present invention relates to an adjustable blade apparatus having an operative surface which cooperates with a forming wire of a forming section. More specifically, the present invention relates to an adjustable blade apparatus which permits adjustment of the distance of an operative surface of a forming blade relative to a forming wire.
2. Information Disclosure Statement
In the papermaking art, stock is ejected from a headbox onto a forming wire of a forming section such that water within the stock is permitted to drain through the forming wire leaving a mat of damp fibers on the moving surface of the forming wire.
Typically, the forming wire moves over the surface of a plurality of forming blades which assist in the removal of water from the stock through the forming wire. Each blade includes an operative surface which comes into physical contact with the side of the forming wire disposed opposite the stock. Usually, such blades are formed from ceramic material for reducing frictional wear that would occur between the moving forming wire and the stationary blade.
Although in the prior art, forming sections typically include a single forming wire or fourdrinier wire, more recently, twin wire formers have been built in which stock is ejected into a forming section defined between cooperating wires of the aforementioned twin wire formers.
In a twin wire former, blades are located within the respective loops of each forming wire with such blades being disposed adjacent to each other. Consequently, there exists a need to accurately adjust the height of the operative surface of each blade relative to the adjacent supported wire. For example, in the case of a Bel Baie III Twin Wire Former, a gap of 0.62 inches exists between adjacent blades. The aforementioned distance or gap between the adjacent blades that the height of each operative surface of each blade must be the same to within a height tolerance within a range + or -0.0015 inches.
A blade of the aforementioned type is typically supported by support means rigidly secured to a framework so that each machine part is built to a particular tolerance. Accordingly, it is not uncommon in view of the number of parts involved for the blade to be supported within a tolerance of the order + or -0.011 inches.
Therefore, in order to obtain the aforementioned required tolerance within the range + or -0.0015 inches, it becomes necessary to carefully add shims every 12 inches across the machine in order to adjust the operative surface to within the required tolerance.
Such shimming or adjusting of the blades for the aforementioned Bel Baie III Former or a Bel Bond retrofit unit would cost in the order of $40,000. Bel Baie and Bel Bond are required trademarks of Beloit Corporation.
The present invention provides means for achieving an adjustable height blade by the provision of a sloping rail to which the blade is affixed.
For example, when the sloping rail of a stationary support means slopes from front to back, a distance of 0.002 inches per inch in a cross machine direction the distance between the operative surface of the blade and the wire can be adjusted 0.006 inches by moving the blade 3 inches in an axial direction along the rail.
Therefore, it is a primary objective of the present invention to provide an adjustable blade apparatus which overcomes the aforementioned inadequacies of the prior art arrangements and which makes a considerable contribution to the art of forming a paper web in a forming section.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art from a consideration of the detailed description taken in conjunction with the annexed drawings.